create a form of propulsion based on the
molecular polarization of water, you could
possibly feasible have on propeller but only
rudders,

the power from the body of the craft being
in a form of perpetual energy situation due
to the motion of the water & the scaling
of the hull creating the propulsion due to
the scaling of the vessel having a scale that
creates the motion of water that in turn
creates the vessel's motion,

have a few Iris over the body like the Iris
on Stargate, this to manage speeds &
changes in whatever,

have scales like a dragon for the water
to slip through for propulsion,